1 files changed, 70 insertions, 6 deletions

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index f0b5c5f2f629..a8ec4b1eec58 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -807,6 +807,8 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
         struct rdma_conn_param conn_param;
         struct ib_qp_init_attr qp_attr;
         struct ib_device_attr devattr;
+        int dma_mr_acc;
+        int need_dma_mr;
         int ret;
         int i;
 
@@ -922,15 +924,77 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
         }
         newxprt->sc_qp = newxprt->sc_cm_id->qp;
 
-        /* Register all of physical memory */
-        newxprt->sc_phys_mr = ib_get_dma_mr(newxprt->sc_pd,
-                                            IB_ACCESS_LOCAL_WRITE |
-                                            IB_ACCESS_REMOTE_WRITE);
-        if (IS_ERR(newxprt->sc_phys_mr)) {
-                dprintk("svcrdma: Failed to create DMA MR ret=%d\n", ret);
+        /*
+         * Use the most secure set of MR resources based on the
+         * transport type and available memory management features in
+         * the device. Here's the table implemented below:
+         *
+         *              Fast    Global  DMA     Remote WR
+         *              Reg     LKEY    MR      Access
+         *              Sup'd   Sup'd   Needed  Needed
+         *
+         * IWARP        N       N       Y       Y
+         *              N       Y       Y       Y
+         *              Y       N       Y       N
+         *              Y       Y       N       -
+         *
+         * IB           N       N       Y       N
+         *              N       Y       N       -
+         *              Y       N       Y       N
+         *              Y       Y       N       -
+         *
+         * NB:  iWARP requires remote write access for the data sink
+         *      of an RDMA_READ. IB does not.
+         */
+        if (devattr.device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
+                newxprt->sc_frmr_pg_list_len =
+                        devattr.max_fast_reg_page_list_len;
+                newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_FAST_REG;
+        }
+
+        /*
+         * Determine if a DMA MR is required and if so, what privs are required
+         */
+        switch (rdma_node_get_transport(newxprt->sc_cm_id->device->node_type)) {
+        case RDMA_TRANSPORT_IWARP:
+                newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_READ_W_INV;
+                if (!(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG)) {
+                        need_dma_mr = 1;
+                        dma_mr_acc =
+                                (IB_ACCESS_LOCAL_WRITE |
+                                 IB_ACCESS_REMOTE_WRITE);
+                } else if (!(devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
+                        need_dma_mr = 1;
+                        dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
+                } else
+                        need_dma_mr = 0;
+                break;
+        case RDMA_TRANSPORT_IB:
+                if (!(devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
+                        need_dma_mr = 1;
+                        dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
+                } else
+                        need_dma_mr = 0;
+                break;
+        default:
                 goto errout;
         }
 
+        /* Create the DMA MR if needed, otherwise, use the DMA LKEY */
+        if (need_dma_mr) {
+                /* Register all of physical memory */
+                newxprt->sc_phys_mr =
+                        ib_get_dma_mr(newxprt->sc_pd, dma_mr_acc);
+                if (IS_ERR(newxprt->sc_phys_mr)) {
+                        dprintk("svcrdma: Failed to create DMA MR ret=%d\n",
+                                ret);
+                        goto errout;
+                }
+                newxprt->sc_dma_lkey = newxprt->sc_phys_mr->lkey;
+        } else
+                newxprt->sc_dma_lkey =
+                        newxprt->sc_cm_id->device->local_dma_lkey;
+
         /* Post receive buffers */
         for (i = 0; i < newxprt->sc_max_requests; i++) {
                 ret = svc_rdma_post_recv(newxprt);